Windows 10 Anniversary Update Knocks Out Webcams

Microsoft admits that the Windows 10 Anniversary Update, which includes Bash support, Windows Ink and a smarter Cortana, has made webcams virtually useless for possibly millions of users.

Add webcams to the list of hardware that has succumbed to the Windows 10 Anniversary Update, leaving users scrambling for answers on how to restore functionality that worked just fine in older versions of the operating system.
This month's update was supposed to put a new, developer-friendly spin on Windows 10. New and enhanced features like Bash support, Windows Ink and a smarter Cortana, Microsoft's virtual assistant technology, promised to help users get more out of the stock Windows experience.
Instead, several users have run into hardware-related issues since its release on Aug. 2. For instance, some PC configurations with the OS installed on a solid-state drive (SSD) freeze during startup, effectively locking out their owners after the update is applied.
Microsoft is investigating the issue. Meanwhile, the company is recommending that users revert to the previous version of Windows 10 within the 10-day window in which the fallback option is available after the Anniversary Update is installed. Microsoft's support forums also contain tips from users who have successfully gained entry into their locked systems, including removing and updating old antivirus software or logging in with a second user account, an action that somehow repairs an inoperative main account.

Now, owners of several popular webcams are discovering that the Anniversary Update has frozen out their cameras, turning simple tasks like conducting video calls or recording a podcast into a troubleshooting saga. The issue stems from changes in how the operating system now handles MJPEG and H.264 streams.

"One of the main reasons that Windows is decoding MJPEG [Motion JPEG] for your applications is because of performance," wrote Microsoft staffer Mike M. in a Windows Dev Center support forum thread related to the issue. "With the Anniversary Update to Windows 10, it is now possible for multiple applications to access the camera in ways that weren't possible before. It was important for us to enable concurrent camera access, so Windows Hello, Microsoft Hololens and other products and features could reliably assume that the camera would be available at any given time, regardless of what other applications may be accessing it."
This approach avoids the performance hit of multiple applications decoding the same MJPEG stream at the same time. In terms of H.264 decoding, Microsoft tweaked the OS to avoid conflicts between applications.
As it turns out, the changes were being tested in January, well ahead of the Anniversary Update's release this summer. However, the company concedes that it "dropped the ball" on the documentation front.
In terms of a fix, short of tinkering with the Windows registry, affected users have a bit of a wait before their webcams work again.
Microsoft is planning to an update that will repair the MJPEG issue next month. Describing the process of patching the H.264 bug as "more involved," the company will be testing a potential update internally and via the Windows Insider early access program before it is released to the general public.